Chubby Oates

Four mental patients - who, due to unauthorized experiments, believe they're living in a dream and have shed all moral imperatives - escape and find their way to the nearest bus-load of stranded schoolgirls.

The blue crystal that the Doctor took from Metebelis III in a previous adventure is desperately sought by the Eight Legs, a race of mutated spiders, as the final element in their plan for universal domination. With help from an old mentor, the Doctor realises the only way to foil the plot is to make the ultimate sacrifice. The Doctor must risk death to return to the cave of the Great One and save the universe.